Printing apparatus in data issuing instrumentalities

ABSTRACT

Ring-shaped type wheels having type characters formed on the periphery thereof are resiliently supported on a rotatably driven shaft at a normal operating position. A type character is printed on a recording medium at a printing position by stopping the normal rotational movement of a type wheel at a point on the periphery so as to cause the rotational kinetic energy associated with the type wheel to pivotally move the type wheel to the printing position and impact the type character against the recording medium.

Unite States atent 11 1 Decker 1 Apr. 30, 1974 [54] PRINTING APPARATUS IN DATA ISSUING 3,169,474 2/1965 Howard 101/110 INSTRUMENTALITIES 2,818,801 1/1958 Hart et a1 101/110 X 3,303,779 2/1967 Giori 101/376 X Inventor: Herbert Decker, Lauf, Germany 2,746,384 5/1956 Bradley et a1 101 110 x [73] Assignee: Triump Werke Nuernberg A.G.,

Nuemberg, Germany Primary ExaminerRobert E. Pulfrey [22] Filed 7 Dec- 29, 1971- Assistant ExaminerR. T. Rader [2]] Appl. No.: 213,678

[57] ABSTRACT [30] F i Application priority Data Ring-shaped type wheels having type characters 30 1970 Germany 2064446 formed on the perlphery thereof are resiliently supported on a rotatably driven shaft at a normal operat- 52 us. c1. 101/110, 197/49 ing A tYPe is Primed record [51 Int. Cl B41 j 1/60 mg medium at a printmg posmon by Stoppmg 581 Field of Search 197/18, 49, 55; 101/93, mal rtatinal movement of a type whfael at 101/99, 110, 367, 368, 376 the periphery so as to cause the rotational kinetic energy associated with the type wheel to pivotally move 56] References Cited the type wheel to the printing position and impact the UNITED STATES PATENTS type character against the recording medium.

3,362,517 1/1968 Ryan et a1 197/18 16 Claims, 9 Drawing Figures TEBmao m4 380?" 301 saw 2 OF 2 a PRINTING APPARATUS IN DATA ISSUING INSTRUMENTALITIES This invention relates to a data printing apparatus having a rotatably driven type wheel with a plurality of type characters arranged about the periphery for marking a recording medium, and more particularly to a printing apparatus having a plurality of type wheels which are rotatably driven and selectively moved to a printing position for impacting a particular type character against the recording medium.

In a data printer, for example one which may be used in a data processing apparatus or for example with an electronic table calculator, it is desirable that the data printer be capable of printing a succession of characters at a relatively high rate of speed. In addition, particularly when the data printer is used with an electronic table calculator, it is desirable that the printing operation be accomplished with a minimum amount of noise, that the energy requirements necessary to effect a printing operation be minimized, and that the apparatus occupy a minimum amount of space.

In the past, there have been data printers using rotatably driven type wheels with type characters formed about the periphery and which are movable to a printing position for impacting a type character against a recording medium. However, as shown in German CH Pat. 109,322, sometimes the printing mechanism is so bulky that it is not practical to arrange a plurality of print wheels adjacent to each other, and accordingly only a single print wheel is used which must be moved across a line of print, thereby preventing the simultaneous printing of a plurality of characters. In addition, as shown in German Pat. No. 2,001,598 and U. S. Pat. No. 3,169,474, there have been print mechanisms in which rotatably driven type wheels were moved individually from a normal position to a printing position by a separate mechanism. However, the use of a separate mechanism to drive the print wheels from a normal position to a printing position necessitates intermittent power requirements in addition to the power requirements necessary to rotatably drive the print wheels.

Accordingly, an object of the present invention is to provide a data printer having a plurality of rotatably driven type wheels and which is capable of printing simultaneously a plurality of type characters onto a recording material.

Another object of the present invention is to provide a data printer having a plurality of type wheels which are rotatably driven in a minimum amount of space.

A further object of the present invention is to provide a data printer having a plurality of rotatably driven type wheels which may be selectively moved to a printing position by utilizing the rotational kinetic energy of the rotatably driven type wheels.

Still other objects, features and advantages of the present invention will be apparent to those skilled in the art from a reading of the following detailed description of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a data printer according to the present invention with a rotatably driven type wheel in a normal operating position,

FIG. 2 shows the rotatably driven type wheel when a printing operation is initiated,

FIG. 3 shows the type wheel at the printing position with a type character impacting against a platen,

- when a return movement is initiated,

FIG. 5 shows the type wheel returned to the normal operating position,

FIG. 6 shows another embodiment of the type wheel constructed according to the present invention,

FIG. 7 shows a sectional view of FIG. 6 illustrating the manner in which the type wheels may be axially spaced on the drive shaft,

FIG. 8 shows still another embodiment of a type wheel constructed in accordance with the present invention, and

FIG. 9 shows the type wheel of the embodiment shown in FIG. 8 at the printing position with a type character impacting against a platen.

Referring generally to the figures in the drawings, and more particularly to FIG. 1, there is shown a data printer, generally indicated 11, for printing characters or symbols onto a recording medium in response to data signals. The recording medium 13 is located beside a suitable marking material 15, and between a platen 17 which is located at a printing position generally indicated at 19, and a type wheel 21 which is located at a normal operating position generally indicated at 23. The type wheel 21 has a plurality of type characters 25 formed on the periphery thereof, and is rotatably driven in the direction indicated by the arrow shown in FIG. 1. When a selected character is to be printed onto the recording medium 13, the type wheel 21 is moved from the normal operating position 23 to the printing position 19 where the selected type character is impacted against the platen 17. After a line of type has been printed, the recording medium 13 may be 'advanced by a suitable sheet feeding mechanism, not shown, for printing another line of type. In addition, the marking material may be advanced past the printing position 19 in preparation for another printing operation.

As shown, the recording medium 13 is fed upwardly from a suitable supply roll 27 which may be contained in a concave pan 29 formed from a portion of the housing 31 of the data printer 11. The marking material 13 may be located on either side of the recording medium 13, and may be in the form of a suitable inked ribbon. The means for advancing the recording medium 13, and the means for advancing the marking material 15 are not shown, since they form no part of the present invention and may be conventional. Although the platen 17 at the printing position 19 is shown as being in the form of an anvil, it is to be understood that other suitable forms of platens may be used, for example a roller. Furthermore, although only a single type wheel 21 is shown'in FIG. 1, it is to be understood that a plurality of type wheels may be located at the normal operating position and rotatably driven in the direction of the arrow. 1

In the normal operating position, the type wheel 21 is supported for rotation about a normal axis, and may be rotatably driven by drive means in the form of a drive shaft 33 which is rotatable about its axis. To minimize the space required for the data printer 1 1, each of the type wheels 21 may be in the form of a ring having an interior opening or bore 35 through which the drive shaft 33 is received. The type wheel 21 may be rotatably driven in concentric relation with the axis of the rotating drive shaft 33 by suitable resilient biasing means in the form of springs 37 connected between the type wheel 21 and the rotatable drive shaft 33. As shown, the drive shaft 33 has flutes or ribs 33a, 33b, 33c and the springs 37 are each stretched between a suitable projecting eyelet 39a, 39b, 39c formed on the interior surface of the type wheel 21 and an eyelet formed in each of the ribs 33a, 33b, 330 of the drive shaft 33. The type wheel 21 is prevented from relative rotational movement about the drive shaft 33 in the direction of rotation as indicated by the arrow by means of wedge-shaped interior abutments 41 projecting from the interior surface 35 of the type wheel 21 and having forward surfaces 43 engaging the ribs 33a, 33b, 33c of the drive shaft 33.

When a character or other symbol is to be printed onto the recording medium 13 in response to a data signal, the type wheel 21 is moved along a printing path from the normal operating position 23, as shown in FIG. 1, to the printing position 19, as shown in FIG. 3, so as to impact a type character 25 against the recording medium 13. The recording medium 13 and the marking material have been deleted from the remaining figures in the drawings for clarity in showing the operation of the data printer 11 during a printing operation. To move the rotatably driven type wheel 21 along the printing path to the printing position 19, stop means are provided for momentarily stopping the rotational movement of the type wheel at a point angularly spaced from the platen 17 in the direction of rotation of the type wheel and radially spaced from the normal operating axis so as to enable the rotational kinetic energy associated with the type wheel 21 to pivotally move the type wheel 21 forwardly along the printing path to the printing position 19.

As shown, the stop means may be in the form of a plurality of stop abutments 45 formed on the periphery of the type wheel 21 and a stop engaging member in the form of a pawl 47 which is movable into engagement with the stop abutments 45. A stop abutment 45 is formed between each of the plurality of type characters on the periphery of the type wheel 21, and the pawl 47 is supported adjacent the periphery of the type wheel 21 for pivotal movement about a suitable rod or axis 49 located in the housing 31 of the data printer 11. To move the pawl 47 in response to a data signal for printing a selected type character, a solenoid 51 may be provided having a plunger 53 operably connected to the pawl 47 for pivotally moving the pawl 47 about the rod 49 and into engagement with a particular stop abutment 45. To enable simultaneous printing of several type characters along the line of type, each type wheel rotatably driven at the normal operating position is provided with a separate pawl and associated solenoid.

Accordingly, when a particular type character 25 on the type wheel 21 is to be printed onto the recording medium 13, the solenoid 51 is energized in response to a data signal to move the pawl 47 into engagement with a particular stop abutment 45 associated with the type character 25 to be printed, as shown in FIG. 2. When the pawl 47 engages the stop abutment 45, the rotational movement of the type wheel 21 about the normal operating axis is momentarily stopped, and the rotational kinetic energy associated with the type wheel pivotally moves the type wheel 21 about the end of the pawl 47 to bring the selected type character 25 into engagement with the recording medium 13 and press it, along with the ribbon 15, against the platen 19 to appropriately mark the recording medium 13. As more particularly shown in FIG. 3, as the type wheel 21 moves pivotally about the end of the pawl 47 to the printing position 19, the drive shaft 33 continues to rotatably drive the type wheel 21 while the resilient biasing means 37 enables the type wheel to move laterally from the normal operating position 23 to the printing position 19. Accordingly, the type wheel 21 is continuously driven by the drive shaft 33'during the printing operation, and a plurality of type wheels may be operated at the same time without interfering with the printing operation of each other, because the rotational energy associated with the type wheel is used to impact a type character 25 on a particular wheel 21 against the recording medium 13 at the printing position 19.

To return the type wheel 21 from the printing position 19 along the printing path to the normal operating position 23, the pawl 47 is driven from engagement with the stop abutment 45 and returned to its normal position, as shown in FIG. 4. The removal of the pawl 47 from engagement with the stop abutment 45 may be accomplished by suitable spring means, not shown, for driving the pawl 47 to its normal position. Upon removal of the pawl 47 from engagement with the stop abutment 45, the resilient biasing means 37 exerts a return force on the type wheel 21 urging it back to its normal operating position 23 with the axis of the type wheel 21 in concentric relation with the axis of the drive shaft 33, as shown in FIG. 5. Upon the type wheel 21 returning to the normal operating position 23, the forward edges 43 of the interior wedge-shaped stop abutments 41 again engage the ribs 33a, 33b, 33c of the drive shaft 33 to prevent relative rotational movement of the type wheel 21 about the drive shaft 33 in the direction of rotation as indicated by the arrow in FIG. 5.

Another embodiment of the invention is shown in FIGS. 6 and 7, and it is operable in the same manner as previously described in connection with FIGS. 1 5. This embodiment is generally similar to the embodiment shown in FIGS. 1 5, and accordingly similar parts have been identified with like reference numerals. In this embodiment, the type wheel 21 is supported about the rotatably driven shaft 33 by resilient biasing means in the form of leaf springs 55 which are bent into a generally U-shaped configuration and located between the ribs 33a,,33b, 33c of the drive shaft 33, and the interior surface 35 of the type wheel 21. As more particularly shown in FIG. 7, the ribs 33a, 33b, 330 of the drive shaft 33 have recesses 57 formed therein for receiving the interior wedge-shaped abutments 41 formed on the interior surface 35 of the type wheel 21, thus axially locating the type wheel 21 on the drive shaft 33. As more particularly shown in FIG. 6, the re-' cesses 57 formed in the ribs 33a, 33b, 33 c of the drive shaft 33 slant inwardly in a direction opposite to the direction of rotation of the drive shaft 33 so as to provide abutments engaged by the forward edges 43 of the interior wedge-shaped stop abutments 41 of the type wheel 21 during rotational movement in the normal operating position 23.

In addition, each of the U-shaped leaf springs 55 are positioned between the interior surface 35 of the type wheel 21 and the drive shaft 33 by having a slot 59 fonned in one end of the spring 55 for receiving the forward edge 43 of an interior wedge-shaped stop abutment 41, while the bent portion of the U-shaped spring 55 has a generally rectangular opening 61 formed therein for receiving the rearward edge 63 of an adjacent interior wedge-shaped abutment 41. Accordingly, the type wheel 21 is axially positioned on the drive shaft 33 but is capable of movement transversely to the axis of the drive shaft 33 during a printing operation.

Still another embodiment of the invention is shown in FIGS. 8 and 9, and it is operable in the same manner as previously described in connection with FIGS. 1 5. The construction of this embodiment is generally similar to the construction of the embodiment shown in FIGS. 1 5, and accordingly similar parts have been identified with like reference numerals. In this embodiment, the type wheel 21 is connected to a drive shaft 65 having a generally circular cross sectional configuration by resilient biasing means in the form of spring elements 67 which are bent into a generally U-shaped configuration. As shown, the spring elements 67 are suitably secured to the interior portion 35 of the type wheel 21 and may partially lie against the periphery of the generally circular drive shaft 65. The portion of each spring element partially lying against the drive shaft 65 has a projection 69 formed thereon which is received and secured by suitable means in a recess 71 formed in the drive shaft 65. Accordingly, the type wheel 21 is rotatably driven by the drive shaft 65 with the axis of the type wheel 21 being concentric with the axis of the drive shaft 65 by preadjusting the spring elements 67 so that they properly urge the type wheel 21 into concentric relation with the axis of the drive shaft 65.

During a printing operation when the rotational movement of the type wheel 21 is momentarily stopped in the manner previously described by means of a suitable pawl 47, the spring elements 67 are flexed about the axis of the drive shaft 65, as more particularly shown in FIG. 9, to enable the rotatably driven type wheel 21 to pivot about the end of the pawl 47 and impact a type character 25 against a platen 19 at the printing position.

While only a limited number of embodiments have been illustrated and described, it will be apparent to those skilled in the art that various modifications andimprovements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the illustrative embodiments, but only by the scope of the appended claims.

What is claimed is:

1. A printing machine, comprising:

a type wheel having an axis of rotation and a type character on the peripheral surface for impacting against a recording medium at a printing position,

a drive shaft rotatable about its axis for rotatably driving said type wheel and imparting rotational kinetic energy to said type wheel,

support means for resiliently supporting said type wheel on said drive shaft for rotation therewith and urging the axis of rotation of said type wheel into concentric relation with the axis of said drive shaft,

said type wheel having a stop abutment thereon in angular spaced relation relative to the type charac ter,

a stop member located adjacent said type wheel and movable into engagement with the stop abutment to stop the rotational movement of said type wheel 6 about the axis of said drive shaft and enable the rotational kinetic energy of said type wheel to pivot said type wheel about the stop member and displace the axis of rotation of said type wheel from the axis of said drive shaft against the urging of said support means resiliently supporting said type wheel on said drive shaft, and

stop actuating means operable in response to a signal to print the type character of said type wheel on the recording medium at the printing position for moving said stop member into engagement with the stop abutment of said type wheel. 2. A printing machine according to claim 1, and further comprising:

another type wheel in the form of a ring with an interior opening formed therein and having an axis of rotation and a type character on the peripheral surface for impacting against a recording medium at another printing position, said drive shaft being received through the interior opening of said other ring-shaped type wheel,

another support means resiliently supporting said other type wheel on said drive shaft for rotation therewith and urging the axis of rotation of said other type wheel into concentric relation with the axis of said drive shaft,

said other type wheel having a stop abutment thereon in angular spaced relation relative to the type character,

another stop member located adjacent said other type wheel and movable into engagement with the stop abutment of said other type wheel to stop the rotational movement of said other type wheel about the axis of said drive shaft and enable the rotational kinetic energy of said other type wheel to pivot said other type wheel about said other stop member against the urging of said other support means resiliently supporting said other type wheel on said drive shaft, and

another stop actuating means operable in response to a signal to print the type character of said other type wheel on the recording medium at the printing position for moving said other stop member into engagement with the stop abutment of said other type wheel.

3. In a printing machine according to claim 1:

said type wheel being in the form of a ring with an inten'or opening formed therein,

said drive shaft being received through the interior opening of said ring-shaped type wheel, and

said support means resiliently supporting said type wheel on said drive shaft being located between the interior portion of said ring-shaped type wheel and said drive shaft for urging the axis of rotation of said type wheel into concentric relation with the axis of said drive shaft.

4. A printing machine according to claim 3, and further comprising locating means for axially locating said type wheel on said drive shaft.

5. In a printing machine according to claim 3, said support means being in the form of leaf springs located between the interior surface of said ring-shaped type wheel and said drive shaft.

6. In a printing machine according to claim 5:

said leaf springs being bent into a generally U-shapedconfiguration with one end of said leaf springs beingsecured to the interior surface of said ringshaped type wheel,

said drive shaft having recesses formed therein, and

said springs having a projection formed on the other end thereof and received into the recesses in said drive shaft for securing said leaf springs to said drive shaft. I

7. In a printing machine according to claim 3:

said drive shaft having ribs formed thereon, and

said support means being in the form of springs located between the interior surface of said ringshaped type wheel and the ribs formed on said drive shaft.

8. A printing machine according to claim 7, and further comprising:

interior abutments formed on the interior surface of said ring-shaped type wheel for engaging the ribs of said drive shaft, and

said support means resiliently urging the interior abutments of said type wheel into engagement with the ribs of said drive shaft.

9. In a printing machine according to claim 8, said resilient biasing means being in the form of leaf springs bent into a generally U-shaped configuration with one end of each spring lying against a rib of said drive shaft and with the other end of each spring lying against the interior surface of said ring-shaped type wheel.

10. In a printing machine according to claim 9:

said leaf spring having an opening formed in the end thereof lying against the interior surface of said type wheel for receiving a portion of an interior abutment formed on the interior surface of said ring-shaped type wheel, and

said leaf spring having an opening formed in the bent portion thereof for receiving a portion of another interior abutment formed on the interior surface of said ring-shaped type wheel.

11. In a printing machine according to claim 10:

said ribs having recesses formed therein, and

said interior abutments formed on the interior surface of said ring-shaped type wheel being received into the recesses in the ribs for axially positioning said type wheel on said drive shaft.

12. A printing machine, comprising:

a type wheel having an axis of rotation and a plurality of type characters on the periphery thereof for impacting against a recording medium at a printing position,

support means for resiliently supporting said type wheel for rotation about an axis at an operating position in spaced relation from the'printing position,

drive means for rotatably driving said type wheel about said normal operating axis and imparting rotational kinetic energy to said type wheel,

said type wheel having a plurality of stop abutments formed on the periphery thereof with each stop abutment being located between two adjacent type characters,

a stop member located adjacent to the periphery of said type wheel and supported for movement into engagement with a selected stop abutment to stop the rotational movement of said type wheel about the axis at the operating position,

said stop member being located generally perpendicular to the path of printing movement from the axis at the operating position and the printing position,

said stop abutments each being operably associated with a different one of the plurality of type characters on said type wheel, and

stop actuating means operable in response to a signal to print a selected type character on the recording medium for moving said stop member into engagement with the stop abutment associated with the selected type character to stop the. rotational movement of said type wheel and enable the rotational kinetic energy of said type wheel to pivotally move said type wheel about said stop memberwith the axis of rotation of said type wheel being displaced from the axis at the operating position so as to impact the selected type character against the recording medium at the printing position.

13. A printing machine, comprising:

a first type wheel in the form of a ring with an interior opening formed therein and having an axis of rotation and a type character formed on the peripheral surface for impacting against a recording medium at a printing position, i

a second type wheel in the form of a ring with an interior opening formed therein and having an axis of rotation and a type character formed on the peripheral surface for impacting against the recording medium at the printing position,

a drive shaft rotatable about its axis for rotatably driving said first type wheel and said second type wheel and imparting rotational kinetic energy thereto,

a first support means for resiliently supporting said first type wheel on said drive shaft for rotation therewith and for urging the axis of rotation of said first type wheel into concentric relation with the axis of said drive shaft,

a second support means for resiliently supporting said second type wheel on said drive shaft for rotation therewith and for urging the axis of rotation of said second type wheel into concentric relation with the axis of said drive shaft,

said first type wheel having a stop abutment thereon,

said second type wheel having a stop abutment thereon,

a first stop member located adjacent the periphery of said first type wheel at the operating position and movable into engagement with the stop abutment of said first type wheel,

a second stop member located adjacent the periphery of said second type wheel at the operating position and movable into engagement with the stop abutment of said second type wheel,

a first stop actuating means operable in response to a signal to print the type character on said first type wheel onto the recording medium for moving said first stop member into engagement with the stop abutment on said first type wheel to stop the rotational movement of said first type wheel and enable the rotational kinetic energy of said first type wheel to pivotally move said first type wheel about said first stop member to displace the axis of rotation of said first type wheel from the axis of said drive shaft and impact the type character against the recording medium at the printing position, and

a second stop actuating means operable in response to a signal to print the type character on said second type wheel onto the recording medium for moving said second stop member into engagement with the stop abutment on said second type wheel to stop the rotational movement of said second type wheel and enable the rotational kinetic energy of said second type wheel to pivotally move said second type wheel about said second stop member to displace the axis of rotation of said second type wheel from the axis of said drive shaft and impact the type character against the recording medium at the printing position.

14. A printing apparatus, comprising:

a type wheel having a type character on the peripheral surface for impacting against a recording medium at a printing position,

support means for resiliently supporting said type wheel for rotation about an axis at an operating position located in spaced relation from the printing position, 7

drive means for rotatably driving said type wheel about said axis at the operating position to impart rotational kinetic energy to said type wheel,

said type wheel having a stop abutment thereon in angular spaced relation relative to the type character,

a stop member located adjacent said type wheel at the operating position and movable into engagement with the stop abutment to stop the rotational movement of said type wheel about the axis at the operating position and enable the rotational kinetic energy of said type wheel to pivot said type wheel about said stop member and displace the axis of rotation of said type wheel from the axis at the operating position against the urging of said support means resiliently supporting said type wheel about the axis at the operating position, and

stop actuating means operable in response to a signal to print the type character on the recording medium at the printing position for moving said stop member into engagement with the stop abutment of said type wheel,

15. A printing apparatus according to claim 14:

said stop abutment being located on the periphery of said type wheel,

said stop member being in the form of a pawl located adjacent the periphery of said type wheel at the operating position and being supported for pivotal movement into the path of said stop abutment on the periphery of said stop wheel, and

said stop actuating means being in the form of a solenoid having a plunger operably connected to said pawl and being energizable to move said pawl into the path of said stop abutment upon receipt of an electrical signal to print the type character of said type wheel.

16. In a printing machine according to claim 8:

said type wheel having means adjacent the interior surface for securing a spring thereto,

said drive shaft having means for securing a spring to the ribs thereof, and

said support means being in the form of tension springs stretched between the spring-securing means of said type wheel and the spring-securing means of said drive shaft for urging the interior abutments of said type wheel into engagement with the ribs of said drive shaft. 

1. A printing machine, comprising: a type wheel having an axis of rotation and a type character on the peripheral surface for impacting against a recording medium at a printing position, a drive shaft rotatable about its axis for rotatably driving said type wheel and imparting rotational kinetic energy to said type wheel, support means for resiliently supporting said type wheel on said drive shaft for rotation therewith and urging the axis of rotation of said type wheel into concentric relation with the axis of said drive shaft, said type wheel having a stop abutment thereon in angular spaced relation relative to the type character, a stop member located adjacent said type wheel and movable into engagement with the stop abutment to stop the rotational movement of said type wheel about the axis of said drive shaft and enable the rotational kinetic energy of said type wheel to pivot said type wheel about the stop member and displace the axis of rotation of said type wheel from the axis of said drive shaft against the urging of said support means resiliently supporting said type wheel on said drive shaft, and stop actuating means operable in response to a signal to print the type character of said type wheel on the recording medium at the printing position for moving said stop member into engagement with the stop abutment of said type wheel.
 2. A printing machine according to claim 1, and further comprising: another type wheel in the form of a ring with an interior opening formed therein and having an axis of rotation and a type character on the peripheral surface for impacting against a recording medium at another printing position, said drive shaft being received through the interior opening of said other ring-shaped type wheel, another support means resiliently supporting said other type wheel on said drive shaft for rotation therewith and urging the axis of rotation of said other type wheel into concentric relation with the axis of said drive shaft, said other type wheel having a stop abutment thereon in angular spaced relation relative to the type character, another stop member located adjacent said other type wheel and movable into engagement with the stop abutment of said other type wheel to stop the rotational movement of said other type wheel about the axis of said drive shaft and enable the rotational kinetic energy of said other type wheel to pivot said other type wheel about said other stop member against the uRging of said other support means resiliently supporting said other type wheel on said drive shaft, and another stop actuating means operable in response to a signal to print the type character of said other type wheel on the recording medium at the printing position for moving said other stop member into engagement with the stop abutment of said other type wheel.
 3. In a printing machine according to claim 1: said type wheel being in the form of a ring with an interior opening formed therein, said drive shaft being received through the interior opening of said ring-shaped type wheel, and said support means resiliently supporting said type wheel on said drive shaft being located between the interior portion of said ring-shaped type wheel and said drive shaft for urging the axis of rotation of said type wheel into concentric relation with the axis of said drive shaft.
 4. A printing machine according to claim 3, and further comprising locating means for axially locating said type wheel on said drive shaft.
 5. In a printing machine according to claim 3, said support means being in the form of leaf springs located between the interior surface of said ring-shaped type wheel and said drive shaft.
 6. In a printing machine according to claim 5: said leaf springs being bent into a generally U-shaped configuration with one end of said leaf springs being secured to the interior surface of said ring-shaped type wheel, said drive shaft having recesses formed therein, and said springs having a projection formed on the other end thereof and received into the recesses in said drive shaft for securing said leaf springs to said drive shaft.
 7. In a printing machine according to claim 3: said drive shaft having ribs formed thereon, and said support means being in the form of springs located between the interior surface of said ring-shaped type wheel and the ribs formed on said drive shaft.
 8. A printing machine according to claim 7, and further comprising: interior abutments formed on the interior surface of said ring-shaped type wheel for engaging the ribs of said drive shaft, and said support means resiliently urging the interior abutments of said type wheel into engagement with the ribs of said drive shaft.
 9. In a printing machine according to claim 8, said resilient biasing means being in the form of leaf springs bent into a generally U-shaped configuration with one end of each spring lying against a rib of said drive shaft and with the other end of each spring lying against the interior surface of said ring-shaped type wheel.
 10. In a printing machine according to claim 9: said leaf spring having an opening formed in the end thereof lying against the interior surface of said type wheel for receiving a portion of an interior abutment formed on the interior surface of said ring-shaped type wheel, and said leaf spring having an opening formed in the bent portion thereof for receiving a portion of another interior abutment formed on the interior surface of said ring-shaped type wheel.
 11. In a printing machine according to claim 10: said ribs having recesses formed therein, and said interior abutments formed on the interior surface of said ring-shaped type wheel being received into the recesses in the ribs for axially positioning said type wheel on said drive shaft.
 12. A printing machine, comprising: a type wheel having an axis of rotation and a plurality of type characters on the periphery thereof for impacting against a recording medium at a printing position, support means for resiliently supporting said type wheel for rotation about an axis at an operating position in spaced relation from the printing position, drive means for rotatably driving said type wheel about said normal operating axis and imparting rotational kinetic energy to said type wheel, said type wheel having a plurality of stop abutments formed on the periphery thereof with each stop abutment bEing located between two adjacent type characters, a stop member located adjacent to the periphery of said type wheel and supported for movement into engagement with a selected stop abutment to stop the rotational movement of said type wheel about the axis at the operating position, said stop member being located generally perpendicular to the path of printing movement from the axis at the operating position and the printing position, said stop abutments each being operably associated with a different one of the plurality of type characters on said type wheel, and stop actuating means operable in response to a signal to print a selected type character on the recording medium for moving said stop member into engagement with the stop abutment associated with the selected type character to stop the rotational movement of said type wheel and enable the rotational kinetic energy of said type wheel to pivotally move said type wheel about said stop member with the axis of rotation of said type wheel being displaced from the axis at the operating position so as to impact the selected type character against the recording medium at the printing position.
 13. A printing machine, comprising: a first type wheel in the form of a ring with an interior opening formed therein and having an axis of rotation and a type character formed on the peripheral surface for impacting against a recording medium at a printing position, a second type wheel in the form of a ring with an interior opening formed therein and having an axis of rotation and a type character formed on the peripheral surface for impacting against the recording medium at the printing position, a drive shaft rotatable about its axis for rotatably driving said first type wheel and said second type wheel and imparting rotational kinetic energy thereto, a first support means for resiliently supporting said first type wheel on said drive shaft for rotation therewith and for urging the axis of rotation of said first type wheel into concentric relation with the axis of said drive shaft, a second support means for resiliently supporting said second type wheel on said drive shaft for rotation therewith and for urging the axis of rotation of said second type wheel into concentric relation with the axis of said drive shaft, said first type wheel having a stop abutment thereon, said second type wheel having a stop abutment thereon, a first stop member located adjacent the periphery of said first type wheel at the operating position and movable into engagement with the stop abutment of said first type wheel, a second stop member located adjacent the periphery of said second type wheel at the operating position and movable into engagement with the stop abutment of said second type wheel, a first stop actuating means operable in response to a signal to print the type character on said first type wheel onto the recording medium for moving said first stop member into engagement with the stop abutment on said first type wheel to stop the rotational movement of said first type wheel and enable the rotational kinetic energy of said first type wheel to pivotally move said first type wheel about said first stop member to displace the axis of rotation of said first type wheel from the axis of said drive shaft and impact the type character against the recording medium at the printing position, and a second stop actuating means operable in response to a signal to print the type character on said second type wheel onto the recording medium for moving said second stop member into engagement with the stop abutment on said second type wheel to stop the rotational movement of said second type wheel and enable the rotational kinetic energy of said second type wheel to pivotally move said second type wheel about said second stop member to displace the axis of rotation of said second type wheel from the axis of said drive shaft and impact the type character against the recording medium At the printing position.
 14. A printing apparatus, comprising: a type wheel having a type character on the peripheral surface for impacting against a recording medium at a printing position, support means for resiliently supporting said type wheel for rotation about an axis at an operating position located in spaced relation from the printing position, drive means for rotatably driving said type wheel about said axis at the operating position to impart rotational kinetic energy to said type wheel, said type wheel having a stop abutment thereon in angular spaced relation relative to the type character, a stop member located adjacent said type wheel at the operating position and movable into engagement with the stop abutment to stop the rotational movement of said type wheel about the axis at the operating position and enable the rotational kinetic energy of said type wheel to pivot said type wheel about said stop member and displace the axis of rotation of said type wheel from the axis at the operating position against the urging of said support means resiliently supporting said type wheel about the axis at the operating position, and stop actuating means operable in response to a signal to print the type character on the recording medium at the printing position for moving said stop member into engagement with the stop abutment of said type wheel,
 15. A printing apparatus according to claim 14: said stop abutment being located on the periphery of said type wheel, said stop member being in the form of a pawl located adjacent the periphery of said type wheel at the operating position and being supported for pivotal movement into the path of said stop abutment on the periphery of said stop wheel, and said stop actuating means being in the form of a solenoid having a plunger operably connected to said pawl and being energizable to move said pawl into the path of said stop abutment upon receipt of an electrical signal to print the type character of said type wheel.
 16. In a printing machine according to claim 8: said type wheel having means adjacent the interior surface for securing a spring thereto, said drive shaft having means for securing a spring to the ribs thereof, and said support means being in the form of tension springs stretched between the spring-securing means of said type wheel and the spring-securing means of said drive shaft for urging the interior abutments of said type wheel into engagement with the ribs of said drive shaft. 